This invention relates generally to the field of food serving dishes or bowls typically used for buffet type serving by restaurant and similar facilities, and more particularly to an improved form of chafing device adapted to preserve the contents at a predetermined heated temperature over a substantial period of time.
It is known in the art to provide chafing dish devices having a base element adapted to be supported by a serving table along with similar devices containing other items of food. Means in the form of replaceable trays are selectively engaged upon the base element with a fresh supply of a particular food as the contents of an installed tray are removed. The base element includes a movably supported cover usually pivotally engaged along an edge thereof which is manually opened by a user to permit access to the contents of the tray, following which the cover is manually closed. In some cases, the cover is counterbalanced to remain in relatively open condition. In the case of relatively larger base elements there is provided heating means, typically using solid alcohol fuel to replace heat lost from the food during the period in which the cover is opened.
Such devices have been known in the art for many years. The principal problem from the standpoint of a user is that he or she, prior to opening the cover, is already carrying at least one plate or dish, and must perform the operation of opening the cover, transferring a desired portion of food, and closing the cover with another hand, as well as replacing a serving implement while maintaining the plate or plates in horizontal orientation. As a result, the user, particularly if elderly, often chooses or neglects to close the cover which remains in opened condition until the arrival of the next user, with undesirable heat loss in the remaining contents of the tray.
Most chafing dishes use friction mechanisms to keep the cover open during serving. Attempts have been made in the past to balance the cover with various spring mechanisms. One type used a cam, cam follower and spring to match the varying forces needed to balance the cover at different open positions. This proved uneconomical and impractical, due mostly to the maintenance requirements. Another type uses a torsion spring mounted axially on the cover shaft. When the cover is opened more than half way, the increasing spring forces become excessive, and must be overcome by friction.
In accordance with the present invention, the device uses a spring with an arm and link mechanism, which closely matches the increasing and decreasing torque required as the cover is moved from closed to half open to full open position. Because of the geometry of the mechanism, the spring balancing torque can decrease, even when the spring force is increasing. The cover can be moved effortlessly to any position, and stops in any position. The mechanism works with an extension spring on a rectangular chafing dish, or when space is a problem, such as on a round chafing dish, a torsion spring can be used.